Devices and methods for visualizing the interior of pipes or other cavities are known in the art. For example, video pipe inspection systems typically include a video camera head at the end of a cable that is manually forced down the pipe to display the pipe interior on a video display. The inspection is commonly recorded using a video recorder (VCR) or digital video recorder (DVR).
Conventional video pipe inspection systems have included a semi-rigid push-cable that provides an electromechanical connection between a rugged camera head that houses the video camera, and a rotatable push reel used to pay out cable and force the camera head down the pipe. Existing push-cables used for such inspections are often helically wrapped with filler rods and conductors wound around a semi-rigid central push-rod. The central push-rod is typically a high-strength rod of composite material, such as fiberglass, which provides the stiffness necessary to push the cable a considerable distance, yet flexible enough to allow sharp turn in pipes and other conduits or voids.
However, current video push-cable constructions utilize a miniature seventy-five ohm impedance coaxial cable to carry the video signal, which must be handled carefully to avoid breakage, and tends to have high losses and reduced signal strength of the transmitted video signal over lengths greater than one hundred feet. A reduction in video signal strength results in a loss of fine detail or resolution as well as image contrast in the displayed video.
Accordingly, there is a need in the art to address the above-described as well as other problems.